noun
Refers to a person who has drifted into a place, often with a sense of being rootless or of uncertain background. Can carry a slightly rough or romantic nuance depending on context.
彼は町にやって来た流れ者だった。
He was a drifter who came to town.
流れ者が酒場にふらりと入ってきた。
A wanderer casually walked into the bar.
Compound of 流れ (nagare, 'flowing, drifting') and 者 (mono, 'person'). The exact historical derivation is uncertain, but the word has long been used to describe a person who drifts from place to place.